ISC 2.2 Hangs on disk I/O

[Doug MacKenzie]

I have a Modular Circuit Technology's 25MHz cache 386 system.
I have a Western Digital WD1006V-SR2 RLL controller with a Segate
ST-277-1 65MB RLL Harddisk with DOS in the first ~8Meg partion and
ISC 2.2 UNIX in the rest.  /etc/partions contains an accurate map
of the bad sectors in the unix partion.

The problem:
  Some times during disk I/O, the disk light will just stay on solid
  and the system is locked up.  I can not get any response other than
  turning the stupid thing off.

  It happens sometimes during boot up when it is scanning the disk.
  It happens sometimes during large GREP's.
  It just seems to happen!!!
  This is not a panic.  It is just hung.

Does anyone have any ideas?

		Doug MacKenzie
		doug at cc.gatech.edu